The present disclosure relates to a semiconductor structure, and particularly to a dynamic random access memory (DRAM) cell including a finFET access transistor and a method of manufacturing the same.
Trench capacitors are used in a variety of semiconductor chips for high areal capacitance and low device leakage. Typically, a trench capacitor provides a capacitance in the range from 4 fF (femto-Farad) to 120 fF. A trench capacitor may be employed as a charge storage unit in a dynamic random access memory (DRAM), which may be provided as a stand-alone semiconductor chip, or may be embedded in a system-on-chip (SoC) semiconductor chip. A trench capacitor may also be employed in a variety of circuit applications such as a charge pump or a capacitive analog component in a radio-frequency (RF) circuit.
The inner electrode of each trench capacitor needs to be electrically connected to a source region of an access transistor. Electrical isolation of each conductive strap providing an electrical path between the inner electrode of a trench capacitor and an access transistor is difficult because misalignment of the conductive strap can cause electrical shorts between the inner electrode and neighboring conductive components of semiconductor devices.